The Phantom of the Opera is set at the Palais Garnier opera house in Paris, France in the 1880s. This building comprises a labyrinthine structure with staircases, trapdoors, passageways, and an underground lake. Leroux's descriptions were inspired by legends and historical events surrounding the real Palais Garnier, which was designed by Charles Garnier and opened in 1875.
The setting of this novel is far more than just a backdrop; it also moves the plot forward. For example, in Chapter 26, Erik kidnaps Christine and tells her he will blow up the opera house if she does not marry him:
I am the Master of the Traps, and open and shut what I please, when I please. Look at the sweet little creatures inside these delicate ebony caskets, mademoiselle. Don’t they look real? Don’t they seem harmless? But, as the saying goes, appearances can be deceptive [...] Should you choose the grasshopper, mademoiselle, we shall all die. There is enough gunpowder under our feet to blow up an entire district of Paris. But if you choose the scorpion, mademoiselle, the gunpowder store shall be flooded. And thus you will grant the gift of life to several hundred Parisians who are at this very moment applauding a rather mediocre masterpiece by Meyerbeer.
Here, Erik presents Christine with two options. The first is to choose the grasshopper, refuse his marriage proposal, and cause him to blow up the opera and everyone at that evening's performance. The second is to choose the scorpion, agree to marry Erik, and save the opera-goers.
The opera house also functions as a contemporary gothic setting; it resembles a cathedral in its size and grandeur. Leroux rarely describes it in a sweeping panorama but rather provides clues about its inner workings during key scenes. The scene-by-scene revelations of trapdoors, secret rooms, and torture chambers create a sense of awe and dread in anticipation of the next discovery. Thus the story's setting is as mysterious as its protagonist.
